Described below is an organic electronic component having a substrate, a first electrode, a second electrode and at least one electron-conducting layer disposed between the first and second electrodes. The electron-conducting layer includes a salt-type derivative of a phosphorus oxo compound as n-dopant. This layer sequence may be embedded into a complex component, for example an OLED.
The fact that the electron conductivity of organic layers can be enhanced by general doping with extraneous substances is sufficiently well known. If the compounds which are to be used as dopants exhibit a suitable HOMO/LUMO (highest occupied molecular orbital/lowest unoccupied molecular orbital) in relation to the organic matrix, an electron may be transferred from the dopant to the matrix, resulting in a consequential rise in the charge carrier density and hence generally in the conductivity of the organic, electrically conductive layer. This mechanism generally forms one of the fundamentals of the setup and for optimization of organic electronic components.
Depending on their functionality, the abovementioned organic components can be divided into groups capable of                converting light to electrical current, for example organic solar cells having a structure as shown in schematic form in FIG. 1,        generating light from electrical current, for example organic light-emitting diodes having a structure as shown schematically in FIG. 2, and        controlling electrical current, for example organic field-effect transistors having a structure as shown schematically in FIG. 3.        
A common factor to all the component classes is that the quality of the components results essentially from the charge carrier density and mobility of the organic layers used.
There are basically two different methods used in organic electronics to increase electron conductivity. Firstly, an increase in the charge carrier mobility can be achieved by the insertion of an intermediate layer between the cathode and electron transport layer. Secondly, n-doping of electrically conductive organic matrix materials with donors of different strength is the second option.
For the former method, often thin salt layers which lower the work function of the electrons, composed of LiF, CsF or, in the more recent literature, cesium carbonate, are used. The properties and effects of cesium carbonate are described, for example, by Huang, Jinsong et al., Adv. Funct. Mater. 2007, 00, 1-8; Wu, Chih-I et al., APPLIED PHYSICS LETTERS 88, 152104 (2006) and Xiong, Tao et al., APPLIED PHYSICS LETTERS 92, 263305 (2008). These intermediate layers significantly improve electron transport, but this improvement is inadequate for high-efficiency components.
For doping of electronic transport layers, in contrast, it is generally the case that substances having a HOMO (highest occupied molecular orbital) above the LUMO (lowest unoccupied molecular orbital) of the matrix material are used. This is a prerequisite for transfer of an electron from the dopant to the matrix material and thus for an increase in its conductivity. In addition, it is desirable to introduce substances whose valence electrons have very low work functions or ionization energies. This too can facilitate the electron release of the dopant and increase the layer conductivity.
The literature cites successful dopants containing alkali metals and alkaline earth metals or lanthanoids as cations. For example, the use of dipotassium phthalate is described by Meng-Huan Ho et al. (Applied Physics Letters 93, 083505, 2008). Other approaches, as pursued, for example, by Schmid et al. (Organic Electronic Conference; Sep. 24-26, 2007, Frankfurt, Germany) and Meng-Huan Hoa et al. (Applied Physics Letters 91, 233507; 2007), are concerned with the use of cesium carbonate for doping of electron conductors in OLEDs. The latter found that the improvements in the conductivity of the matrix layer achievable through cesium salt doping are essentially a function of the anion of the evaporated salt. In addition, it was shown that the anion exerts a relatively small influence on the evaporability of the compound as such. This evaporation temperature is of course an important parameter in the processibility of the compound and, for energetic reasons, a high evaporation temperature in the process regime is disadvantageous.
A high evaporation temperature is also disadvantageous in the use of cesium phosphate as dopant, as disclosed, for example, in WO 2011 039323 A2. Although it is possible to obtain very good n-conductivities of organic layers through doping with this salt, it is necessary to work with high sublimation temperatures because of the salt-type character of the dopant, which makes the doping difficult in terms of process technology.